Aircraft: EMB ERJ 145 ER/LR
Phase of flight: Taxi
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence

During an icing configuration takeoff; we received an EICAS message for BLD 2 VALVE CLS upon reaching 500 FT AGL. After referring to the Quick Reference Handbook; we were unable to have the displayed message remove for the duration of the flight. As per the guidance in the QRH; we were limited to an altitude of FL250. Icing was forecasted and expected along the route which would have limited us further to 15;000 FT. Because of the careful planning by Dispatch on our release fuel; we would not have enough fuel to reach destination at FL250; yet alone at 15;000 FT for that matter should we encounter icing conditions. Neither could we make our planned alternate. After informing Dispatch of our situation; they advised us to air return. We did so.The Captain and I had some foreknowledge of the possibility of the BLD 2 VALVE CLS occurring. As we arrived to the aircraft; the flight crew who brought the airplane in made an entry in the logbook for BLD 2 VALVE CLS. The crew had told us the message appeared in flight and that as soon as they landed; the message went away. Maintenance came on board to take a look. The first Mechanic that looked into it told us they were going to need another bleed valve. The Captain and I heard the Mechanic radio in to see if they had the part. However; the Mechanic was on his way out of the airplane as he made the radio call. The Captain and I never knew the 'status' of the part; nor did we ever see that Mechanic again. After a few minutes went by; a different Mechanic comes onboard and maybe even eventually a third to look into the situation. Finally; one of the Mechanics said it was fine and that he completed the logbook and we are good to go. I was suspicious of his tone; body language; and eye contact as he informed us and left the aircraft. The Captain and I discussed our thoughts on the matter. We felt operationally obligated to accept the aircraft. We understood; given the recent mechanical history; current weather and fuel requirement related issues; the possibility of returning if the Bleed 2 Valve should fail closed again. We had planned; and briefed for the possibility of an air return before pushing back from the gate. We were able to execute our plan as the situation became necessary.With the exception of refusing to take the aircraft; or working with Dispatch for more fuel further restricting the amount of passengers we could take; I'm not sure there was much more we as a crew could do to improve this situation. In working with other team members; we must respect their jobs and professional skills. In doing so; we must make sure that we comply with operational policies and regulations as they apply to us. I believe we did so. But above this; we must also be aware of the situation for what it is; and develop a plan should the foreseeable arise. EMB145 First Officer experiences an EICAS message for BLD 2 VALVE CLS shortly after takeoff in icing conditions. With the restrictions this anomaly places on the aircraft the crew elects to return to the departure airport. This valve had been written up by the previous crew and Maintenance had signed it off as 'ground checks OK.'